Particularly milling tools which are fitted with exchangeable indexable inserts have a tool body on which one or more insert seats for corresponding indexable inserts are formed. It is frequently required that individual indexable inserts are adjustable in their axial position. This measure serves, for example, the purpose of setting a desired number of smoothing cutting edges. In the case of a plain miller, the circumferential cutting edges of which operate at a high metal removal rate as roughing cutting edges for example, it has proved to be expedient for example for only one smoothing cutting edge to be provided for three to five roughing cutting edges in order to obtain a good smoothing finish. It is therefore not at all necessary for all the inserts to be fastened to the tool body in an axially adjustable manner. It is sufficient if one or a few inserts are held by a correspondingly adjustable mounting.
Known from U.S. Pat. No. 3,802,043, which discloses the features of the preamble of patent claim 1, is a milling tool which has a recess for receiving an indexable insert to be adjustably held. Arranged in the recess is a cartridge which has an insert seat. The cartridge, which has a thickness exceeding twice the thickness of the indexable insert, has both a bearing face for the bottom face of the indexable insert and lateral bearing faces. With its rear face, the cartridge bears against a corresponding planar bearing face of the recess of the tool body. A wedge presses the indexable insert into the insert seat of the cartridge and consequently presses the cartridge against the opposite wall of the recess. Serving for adjusting the cartridge in the longitudinal direction is a rotatable cam, which bears with its cam face against an end face of the cartridge.
The cartridges require a certain installation space, with the result that the tooth spacing between successive indexable inserts cannot go below a certain minimum spacing. This restricts the possible number of teeth and consequently the metal removal rate of the milling tool.
In particular in the case of milling tools on which only some of the indexable inserts are to be adjustably mounted, the increased tooth spacing caused by the cartridges has a detrimental effect. If the insert seats for non-adjustably mounted indexable inserts are provided directly on the tool body, the tooth spacings tend to be relatively small. However, in order to achieve a uniform tooth spacing, they must be set to the large tooth spacing dictated by the small number of cartridges.
It is likewise known from the above mentioned U.S. Pat. No. 3,802,043 to mount indexable inserts adjustably without any cartridge. For this purpose there is provided on the tool body an insert seat which has a plane face for the bottom face of the indexable insert. The indexable insert bears laterally with its free face directly against the above mentioned cam. For fastening, the indexable insert is braced by a wedge against the plane face.
In the case of this arrangement, the exact alignment of the insert is dependent on the alignment of the cam. Even slight backlash about its axis of rotation or a small angular error of its axis of rotation or worn points on the insert at the point of contact with the cam may under certain circumstances cause the insert to be wrongly adjusted.
Known from German Patent 674,112 is a cutter head which has cutters mounted in an axially adjustable manner. These are in engagement with the head of an eccentric bolt, the shank of which is seated in a bore of a basic tool body. The cutters are of a correspondingly elongate design and offer sufficient installation space. However, this measure cannot be readily transferred to indexable inserts.
Known from DE 35,30,745 A1 is a cutter head which has a plurality of inserts respectively mounted in cartridges. The cartridges are adjustably held. For this purpose, the cartridges have corresponding insert seats, with the result that the cutting forces are transferred from the corresponding insert initially to the cartridge and from the latter to the tool body. This requires a robust design of the cartridges and consequently a considerable installation space.